Zinc base alloy



Patented Sept. 25, 1945,

ZINC BASE ALLOY Edward 8. Hana, Borne, N. Y., assignor to Revere Copper and Brass Incorporated, Rome, N. Y., a corporation of Maryland No Drawing. Application June 18, 1043, Serial No. 491,081

2 Claims.

My invention, which relates to zinc base alloys. and has among its objects the provision or a zinc base alloy of improved characteristics, will be best understood from the following description, the scope of the invention being more particularly pointed out in the appended claims.

Alloys according to the invention contain 0.76 to 4% copper, 0.05 to 0.25% silver, 0.1 to 0.4% aluminum and 0.1 to 0.5% metal of the group consisting of manganese, iron, nickel and cobalt.

Zinc, it will be understood by those skilled in the art, is a metal oi moderate tensile strength and excellent ductility, and may be worked either hot or cold by commercial mill processes to produce sheets, rods, etc. Zinc, however, has the defect oi seal annealing" when cold worked, and thus. unlike many other metals, cannot be hardsued by cold working. Further, zinc has the most serious defect of being subject to grain growth when subjected to temperatures much in excess of room temperature or when it ages, causing its tensile strength to be seriously reduced and its ductility almost to disappear. For example, hot rolled zinc having a tensile strength of 17,000 pounds per square inch and a ductility represented by an elongation oi 45% in 2 inches will when heated to 600 F. for 1 hour have its tensile strength reduced to 6,000 pounds per square inch and its elongation to 4% in 2 inches, and when subjected to moist steam at 05 C. for days, which is the standard accepted test for determining the effect of age on zinc and its alloys, will have its tensile strength reduced to 11,000 pounds per square inch and its elongation to 2% in 2 inches.

Applicant has found that grain growth in zinc may be much reduced by adding small amounts of copper to it, the copper also markedly increasing its tensile strength. However, as the amount of copper is increased a serious loss in ductility occurs. For example, by progressively adding copper the tensile strength of the zinc may be increased from about 29,000 pounds per square inch with 1% copper to about 45,000 pounds per square inch with 5% copper, but with a decrease in the elongation of from 45% to in 2 inches.

Applicant has found that if small amounts of aluminum, or small amounts of both copper and aluminum, are added to zinc, although much increasing its tensile strength as compared to when copper alone is added, its ductility is reduced to a very unsatisfactory extent, and as the resulting alloy ages causes intercrystalline corrosion and, iurther, sufllcient formation of an additional alloy phase to make the alloy unstable in respect to dimensions, thus making the alloy unsatisfactory in all these respects.

Adding to zinc a small amount of silver with the copper and aluminum, it has been found, will substantially compensate for the defects tended to be imparted by the addition of aluminum in that the silver effectively prevents intercrystalline corrosion, alloy phase change and dimensional instability. With such alloys it is possible to obtain, within the range of l to 4% copper, very high tensile strengths of from 40,000 to 60,000 pounds per square inch. However, the ductility, although far superior to that of the ternary zinc-copper-sluminum alloy, is however commonly within a range represented by 15 to 30% elongation in 2 inches, making these alloys have their greatest field of usefulness for makin articles of high unit strength y hot ioraing operations.

Applicant however has found that if a combination of small amounts of silver and metal of the group consisting of manganese. iron, nickel and cobalt is added to the ternary sine-copperaluminum alloy the ductility of the resulting alloy will be much superior to that of the alloy resulting from adding a small amount of silver alone to the ternary alloy, this superior ductility being secured without a great sacrifice in the high tensile strength of the ternary alloy. For example, within the ranges of 1 to 4% copper and 0.1 to 0.4% aluminum tensile strengths withm the range of about 85,000 to 50,000 pounds per square inch and elongations within the range of 25 to 60% in 2 inches may be secured by adding to the ternary alloy the combination of silver and metal of the group specified. Further, when this combination of metals is added, the stability of the resulting alloy in respect to tensile strength and ductility is much improved as compared to when silver alone is added, for neither the ductility nor tensile strength of the resultv alloy obtained by adding this combination of metals decreases with age, or when the alloy is annealed, as much as when silver alone is added. At the same time the improved alloy does not possess the common defect of being subject to intercrystalline corrosion or deleterious alloy phase change with age commonly encountered when it is attempted to improve the physical properties of zinc by adding small amounts of complex combinations of other elements to it. Likewise the improved alloy is satisiactorily free from grain growth, and is stable in respect to maintaining its dimensions with age. Furthermore, the improved alloy has a higher degree of plasticity in both the cold condition and hot condition than the alloy secured by addin: silver alone to the zinc-copper-aluminum alloy, and may be satisfactorily cold worked either hot or cold by commercial mill processes, say rolled into sheets or employed for moderate deep drawing operations. Still further. the improved alloy has a high degree of toughness measured by its resistance to impact loading or shock. The excellent properties of the improved alloy are exhibited by the following table, in which the steam test" is that above referred to for determining the effect of age on zinc and its alloys:

Hot rolled l 1.. ansmmms rolled igi lfig l hr., and

subiectedto steamtest Cu Ag Al Mn 1* E 'r a 'r n 0 (l 0 l1 5 6 4 B 2 0.15 0.15 0.2.5 0.5 as 2s 00 40 s0 40 4 0.15 0.25 0.1 n 00 40 40 n so 4 on 0.20 0.0 s1 s0 41 40 41 .40

T-wnsile strength in l 000 ds per square inch. it -per cent elongation in 2 Riches.

silver, aluminum and metal of the group specified does not substantially exceed the amount of copper employed. Otherwise no assurance will be had against lntergranular corrosion as the alloy ages. Best results in respect to securing an alloy of all around good properties will be secured within the ranges 01' 1 to 3.5% copper, 0.1 to 0.2% silver, 0.2 to 0.3% aluminum, and 0.1 to 0.5% metal of the group specified.

10 It will be understood that, within the scope of the appended claims, further constituents may be added for modifying the properties of the improved alloy or for securing additional properties, so long. as the characteristics imparted to the zinc by the addition of copper, aluminum, silver, and

metal oi the aroup specified are not substantially destroyed.

I claim:

1. Zinc base alloys having, approximately, 0.75

to copper. 0.05 to 0.25% silver, 0.1 to 0.4%

aluminum, and 0.1 to 0.5% metal of the group consisting of manganese, iron, nickel and cobalt, the sum of the percentage amounts of silver, aluminum. and metal of said group not substantially as exceeding the percentage amount of copper, the

balance being substantially zinc.

2. Zinc base alloys having, approximately, 1 to 3.5% copper, 0.1 to 0.2% silver 0.2 to 0.3% aluminum, and 0.1 to 0.5% metal oi the group The above results the mmmed 8110 will be 39 consisting of manganese, iron, nickel and cobalt,

secured within the ranges oi. constituents above specified provided the sum oi the amounts oi CERTIFICATE OF CORRECTION.

Patent No 2,585,097

the balance being substantially zinc.

EDWARD S. BUNK.

September 2 5, 1914.5

EWARD S. BUNN.

It is hereby certified that error appears in the printed specification oi the above numbered patent requiring correction as follows:

for the word "seal" read --self--; and that the said Letcolumn, line 16,

tors Patent should be read with this correction therein that in the Patent Office.

conform to the record of the case Page 1, first the same may Signed and sealed this th day of December, A. D. 1905.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.

degree of plasticity in both the cold condition and hot condition than the alloy secured by addin: silver alone to the zinc-copper-aluminum alloy, and may be satisfactorily cold worked either hot or cold by commercial mill processes, say rolled into sheets or employed for moderate deep drawing operations. Still further. the improved alloy has a high degree of toughness measured by its resistance to impact loading or shock. The excellent properties of the improved alloy are exhibited by the following table, in which the steam test" is that above referred to for determining the effect of age on zinc and its alloys:

Hot rolled l 1.. ansmmms rolled igi lfig l hr., and

subiectedto steamtest Cu Ag Al Mn 1* E 'r a 'r n 0 (l 0 l1 5 6 4 B 2 0.15 0.15 0.2.5 0.5 as 2s 00 40 s0 40 4 0.15 0.25 0.1 n 00 40 40 n so 4 on 0.20 0.0 s1 s0 41 40 41 .40

T-wnsile strength in l 000 ds per square inch. it -per cent elongation in 2 Riches.

silver, aluminum and metal of the group specified does not substantially exceed the amount of copper employed. Otherwise no assurance will be had against lntergranular corrosion as the alloy ages. Best results in respect to securing an alloy of all around good properties will be secured within the ranges 01' 1 to 3.5% copper, 0.1 to 0.2% silver, 0.2 to 0.3% aluminum, and 0.1 to 0.5% metal of the group specified.

10 It will be understood that, within the scope of the appended claims, further constituents may be added for modifying the properties of the improved alloy or for securing additional properties, so long. as the characteristics imparted to the zinc by the addition of copper, aluminum, silver, and

metal oi the aroup specified are not substantially destroyed.

I claim:

1. Zinc base alloys having, approximately, 0.75

to copper. 0.05 to 0.25% silver, 0.1 to 0.4%

aluminum, and 0.1 to 0.5% metal of the group consisting of manganese, iron, nickel and cobalt, the sum of the percentage amounts of silver, aluminum. and metal of said group not substantially as exceeding the percentage amount of copper, the

balance being substantially zinc.

2. Zinc base alloys having, approximately, 1 to 3.5% copper, 0.1 to 0.2% silver 0.2 to 0.3% aluminum, and 0.1 to 0.5% metal oi the group The above results the mmmed 8110 will be 39 consisting of manganese, iron, nickel and cobalt,

secured within the ranges oi. constituents above specified provided the sum oi the amounts oi CERTIFICATE OF CORRECTION.

Patent No 2,585,097

the balance being substantially zinc.

EDWARD S. BUNK.

September 2 5, 1914.5

EWARD S. BUNN.

It is hereby certified that error appears in the printed specification oi the above numbered patent requiring correction as follows:

for the word "seal" read --self--; and that the said Letcolumn, line 16,

tors Patent should be read with this correction therein that in the Patent Office.

conform to the record of the case Page 1, first the same may Signed and sealed this th day of December, A. D. 1905.

(Seal) Leslie Frazer First Assistant Commissioner of Patents. 

